What is the maximum ringtone length on iPhone?
Apple limits all ringtone files to 40 seconds. Any ringtones longer than this limit will not sync to an iOS device using iTunes.
When it comes to how long a ringtone will play when the iPhone is ringing, this time is shorter. For example, normal ringing on AT&T is limited to 20 seconds. Users can contact their carrier to extend default ring times. Upon request, AT&T will extend rings to 30 seconds before picking up with voice mail, however this is still shorter than the 40 second limit enforced by Apple software.